summaryrefslogtreecommitdiffstats
path: root/drivers/media/rc/ir-rcmm-decoder.c
blob: 028df5cb18281275ab213ef12ca40e5859f21b18 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
// SPDX-License-Identifier: GPL-2.0+
// ir-rcmm-decoder.c - A decoder for the RCMM IR protocol
//
// Copyright (C) 2018 by Patrick Lerda <patrick9876@free.fr>

#include "rc-core-priv.h"
#include <linux/module.h>

#define RCMM_UNIT		166667	/* nanosecs */
#define RCMM_PREFIX_PULSE	416666  /* 166666.666666666*2.5 */
#define RCMM_PULSE_0            277777  /* 166666.666666666*(1+2/3) */
#define RCMM_PULSE_1            444444  /* 166666.666666666*(2+2/3) */
#define RCMM_PULSE_2            611111  /* 166666.666666666*(3+2/3) */
#define RCMM_PULSE_3            777778  /* 166666.666666666*(4+2/3) */

enum rcmm_state {
	STATE_INACTIVE,
	STATE_LOW,
	STATE_BUMP,
	STATE_VALUE,
	STATE_FINISHED,
};

static bool rcmm_mode(const struct rcmm_dec *data)
{
	return !((0x000c0000 & data->bits) == 0x000c0000);
}

static int rcmm_miscmode(struct rc_dev *dev, struct rcmm_dec *data)
{
	switch (data->count) {
	case 24:
		if (dev->enabled_protocols & RC_PROTO_BIT_RCMM24) {
			rc_keydown(dev, RC_PROTO_RCMM24, data->bits, 0);
			data->state = STATE_INACTIVE;
			return 0;
		}
		return -1;

	case 12:
		if (dev->enabled_protocols & RC_PROTO_BIT_RCMM12) {
			rc_keydown(dev, RC_PROTO_RCMM12, data->bits, 0);
			data->state = STATE_INACTIVE;
			return 0;
		}
		return -1;
	}

	return -1;
}

/**
 * ir_rcmm_decode() - Decode one RCMM pulse or space
 * @dev:	the struct rc_dev descriptor of the device
 * @ev:		the struct ir_raw_event descriptor of the pulse/space
 *
 * This function returns -EINVAL if the pulse violates the state machine
 */
static int ir_rcmm_decode(struct rc_dev *dev, struct ir_raw_event ev)
{
	struct rcmm_dec *data = &dev->raw->rcmm;
	u32 scancode;
	u8 toggle;
	int value;

	if (!(dev->enabled_protocols & (RC_PROTO_BIT_RCMM32 |
							RC_PROTO_BIT_RCMM24 |
							RC_PROTO_BIT_RCMM12)))
		return 0;

	if (!is_timing_event(ev)) {
		if (ev.reset)
			data->state = STATE_INACTIVE;
		return 0;
	}

	switch (data->state) {
	case STATE_INACTIVE:
		if (!ev.pulse)
			break;

		if (!eq_margin(ev.duration, RCMM_PREFIX_PULSE, RCMM_UNIT))
			break;

		data->state = STATE_LOW;
		data->count = 0;
		data->bits  = 0;
		return 0;

	case STATE_LOW:
		if (ev.pulse)
			break;

		if (!eq_margin(ev.duration, RCMM_PULSE_0, RCMM_UNIT))
			break;

		data->state = STATE_BUMP;
		return 0;

	case STATE_BUMP:
		if (!ev.pulse)
			break;

		if (!eq_margin(ev.duration, RCMM_UNIT, RCMM_UNIT / 2))
			break;

		data->state = STATE_VALUE;
		return 0;

	case STATE_VALUE:
		if (ev.pulse)
			break;

		if (eq_margin(ev.duration, RCMM_PULSE_0, RCMM_UNIT / 2))
			value = 0;
		else if (eq_margin(ev.duration, RCMM_PULSE_1, RCMM_UNIT / 2))
			value = 1;
		else if (eq_margin(ev.duration, RCMM_PULSE_2, RCMM_UNIT / 2))
			value = 2;
		else if (eq_margin(ev.duration, RCMM_PULSE_3, RCMM_UNIT / 2))
			value = 3;
		else
			value = -1;

		if (value == -1) {
			if (!rcmm_miscmode(dev, data))
				return 0;
			break;
		}

		data->bits <<= 2;
		data->bits |= value;

		data->count += 2;

		if (data->count < 32)
			data->state = STATE_BUMP;
		else
			data->state = STATE_FINISHED;

		return 0;

	case STATE_FINISHED:
		if (!ev.pulse)
			break;

		if (!eq_margin(ev.duration, RCMM_UNIT, RCMM_UNIT / 2))
			break;

		if (rcmm_mode(data)) {
			toggle = !!(0x8000 & data->bits);
			scancode = data->bits & ~0x8000;
		} else {
			toggle = 0;
			scancode = data->bits;
		}

		if (dev->enabled_protocols & RC_PROTO_BIT_RCMM32) {
			rc_keydown(dev, RC_PROTO_RCMM32, scancode, toggle);
			data->state = STATE_INACTIVE;
			return 0;
		}

		break;
	}

	dev_dbg(&dev->dev, "RC-MM decode failed at count %d state %d (%uus %s)\n",
		data->count, data->state, TO_US(ev.duration), TO_STR(ev.pulse));
	data->state = STATE_INACTIVE;
	return -EINVAL;
}

static const int rcmmspace[] = {
	RCMM_PULSE_0,
	RCMM_PULSE_1,
	RCMM_PULSE_2,
	RCMM_PULSE_3,
};

static int ir_rcmm_rawencoder(struct ir_raw_event **ev, unsigned int max,
			      unsigned int n, u32 data)
{
	int i;
	int ret;

	ret = ir_raw_gen_pulse_space(ev, &max, RCMM_PREFIX_PULSE, RCMM_PULSE_0);
	if (ret)
		return ret;

	for (i = n - 2; i >= 0; i -= 2) {
		const unsigned int space = rcmmspace[(data >> i) & 3];

		ret = ir_raw_gen_pulse_space(ev, &max, RCMM_UNIT, space);
		if (ret)
			return ret;
	}

	return ir_raw_gen_pulse_space(ev, &max, RCMM_UNIT, RCMM_PULSE_3 * 2);
}

static int ir_rcmm_encode(enum rc_proto protocol, u32 scancode,
			  struct ir_raw_event *events, unsigned int max)
{
	struct ir_raw_event *e = events;
	int ret;

	switch (protocol) {
	case RC_PROTO_RCMM32:
		ret = ir_rcmm_rawencoder(&e, max, 32, scancode);
		break;
	case RC_PROTO_RCMM24:
		ret = ir_rcmm_rawencoder(&e, max, 24, scancode);
		break;
	case RC_PROTO_RCMM12:
		ret = ir_rcmm_rawencoder(&e, max, 12, scancode);
		break;
	default:
		ret = -EINVAL;
	}

	if (ret < 0)
		return ret;

	return e - events;
}

static struct ir_raw_handler rcmm_handler = {
	.protocols	= RC_PROTO_BIT_RCMM32 |
			  RC_PROTO_BIT_RCMM24 |
			  RC_PROTO_BIT_RCMM12,
	.decode		= ir_rcmm_decode,
	.encode         = ir_rcmm_encode,
	.carrier        = 36000,
	.min_timeout	= RCMM_PULSE_3 + RCMM_UNIT,
};

static int __init ir_rcmm_decode_init(void)
{
	ir_raw_handler_register(&rcmm_handler);

	pr_info("IR RCMM protocol handler initialized\n");
	return 0;
}

static void __exit ir_rcmm_decode_exit(void)
{
	ir_raw_handler_unregister(&rcmm_handler);
}

module_init(ir_rcmm_decode_init);
module_exit(ir_rcmm_decode_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick Lerda");
MODULE_DESCRIPTION("RCMM IR protocol decoder");